Unlocking Tight Carbonate Reservoir Potential: Geological Characterization to Execution

Abstract

The reservoir in discussion is a tight carbonate reservoir with low productivity and relatively under-developed albeit the huge in-place volumes. The expectation is that a detail reservoir characterization will provide insight on factors affecting reservoir productivity, spatial distribution of productive portion of the reservoir and offering solution to overcome reservoir tightness. The case study discusses on how a comprehensive multi-discipline review unravels and presents a robust reservoir heterogeneity framework. A geological review that includes both depositional and diagenetic process is performed to understand distinct components/factors responsible for reservoir heterogeneity. Simultaneously, petrophysical assessment was performed to quantitatively define rock grouping based on porosity-permeability, capillary pressure and pore throat distribution in the log and core domain. The multi-discipline observations were then reconciled to establish relationship between the process origin and the resultant product of specific group/range of reservoir petrophysical properties. The multitude of pore throat characters and its petrophysical properties were linked to the underlying geological processes. The established heterogeneity framework provides clarity on spatial distribution of the reservoir sweet-spot, factors controlling low productivity and the required mitigation. The study provides a complete journey of unlocking tight reservoir potential. It illustrates the geological studies influence toward innovative completion technology selection, design, and execution to overcome reservoir challenge. The study is supported by recent drilling and test results, hence offering insight for adoption and lesson learned.